1. Field of the Invention
This invention is directed towards the Pyros Kinetix reader for conducting assays. More specifically, this invention is directed to providing an analytical device that, in one embodiment, conveniently and accurately assays both turbidity and chromogenic reactions in plural vessels.
2. Discussion of the Background
Optical techniques are commonly used to transduce a number of different chemical and biological parameters. Among many thousand such examples, turbidometric measurements can be used to bioassay and/or bioscreen for the presence of endotoxin using Limulus amebocyte lysate (LAL) such as PYROTELL-T (Associates of Cape Cod, Falmouth, Mass.). Similarly, chromogenic measurements can be used to bioassay and/or bioscreen for the presence of endotoxin using the POLYCHROME chromogenic formulation of LAL (Associates of Cape Cod, Falmouth, Mass.), which releases a yellow chromophore when exposed to endotoxin.
Many different instruments have been described that use optical techniques to transduce these and other such biological parameters. For example, Hoyt (U.S. Pat. No. 4,936,682) describes an instrument for measuring the light absorption characteristics of a plurality of samples arranged in a substantially circular pattern about a single incandescent light source. Incandescent light sources are however only suitable for performing certain types of assays since their emission intensity is primarily in the IR and long wavelength portion of the visible spectrum. Moreover, incandescent light sources require intensity adjustments to maintain a relatively constant emission flux, have limited operational lifetimes, and, as a consequence of resistive heating of the filament, dissipate large amounts of heat that often complicate temperature control in incubators. Finally, since incandescent sources require relatively large amounts of power, they are commonly driven by high power AC sources such as line sources and microcontroller-based modulation of incandescent source intensity is relatively difficult to implement. Shirasawa (U.S. Pat. No. 5,337,139) describes a multichannel optical measuring system which uses multiple branches of a quartz optical fiber to project light from mercury or xenon lamps at glass cuvettes that contain biological cell samples in order to perform fluorometric measurements. Shirasawa (U.S. Pat. No. 5,337,139) also describes that a light emitting diode (LED)/photodiode pair can be associated with each glass cuvette to generate a signal related to the intensity of transmitted light through the cuvette. Mioduski (U.S. Pat. No. 3,882,318) describes a reaction block configured to hold a reaction chamber where a specimen and a test reagent are mixed. The reaction block has two optical paths therethrough, one for conducting a transmittance measurement of the specimen/test reagent mixture, and the other to detect the presence of a reaction chamber within the block. Each reaction block has an associated printed circuit board for detecting light output from both paths. Noeller (U.S. Pat. No. 4,784,947) describes a method for photographically recording fluorometric and nephelometric analyses performed using a photo-flash or a strobe light photon source. As both the light transduction and light generation described by Noeller (U.S. Pat. No. 4,784,947) only occurs at discrete times, continuous monitoring and automated data analysis is not possible.
The disclosure of each of the above-noted patents is incorporated herein by reference.